This began a pattern that was to continue for several years with Campbell guiding Asimov through his formative beginnings as a science fiction writer.

Asimov's association with the field of science fiction has been a long and distinguished one. He is credited with the introduction of several innovative concepts into the genre, including the formulation of the "Three Laws of Robotics." Asimov maintains that Campbell gave the idea for the laws to him; Campbell, on the other hand, said that he had merely picked them out of Asimov's early robot stories. In any case, it was Asimov who first formally stated the three laws: "1. A robot may not injure a human being or, through inaction, allow a human being to come to harm. 2. A robot must obey the orders given it by human beings except where such orders would conflict with the First Law. 3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws." Asimov says that he used these precepts as the basis for "over two dozen short stories and three novels .. about robots," and he feels that he is "probably more famous for them than for anything else I have written, and they are quoted even outside the science-fiction world. The very word `robotics' was coined by me." The three laws gained general acceptance among readers and among other science fiction writers; Asimov, in his autobiography, writes that they "revolutionized" science fiction and that "no writer could write a stupid robot story if he used the Three Laws. The story might be bad on other counts, but it wouldn't be stupid." The laws became so popular, and seemed so logical, that many people believed real robots would eventually be designed according to Asimov's basic principles.

Also notable among Asimov's science fiction works is the "Foundation" series—a group of short stories, published in magazines in the forties and then collected into a trilogy in the early fifties. It was written as a "future history," a story being told in a society of the distant future which relates events of that society's history. Asimov did not invent the concept, but there can be little doubt that he became a master of the technique. Foundation, Foundation and Empire, and Second Foundation have achieved special standing among science fiction enthusiasts. In 1966, the World Science Fiction Convention honored them with a special Hugo Award as the best all-time science fiction series.